$$reference->[m_emailAddress]

##</code><code>##

$$reference->{m_emailAddress}

##</code><code>##

$$reference->{m_emailAddress}->[0]

##</code><code>##

${ $$reference->{m_emailAddress} }->[0]->[0]

##</code><code>##

use strict;
use warnings;

sub print_record {
    my ($rec) = @_;
    print("username:  $rec->{m_username}\n");
    print("password:  $rec->{m_password}\n");
    print("email:     @{ $rec->{m_email_addresses} }\n");
}

my $stg_username        = "PerlMonk";
my $stg_password        = "VeryGoodPassword";
my @stg_email_addresses = ( "Monk1", "Monk2", "Monk3" );

my $ellab_rec = {
    m_username     => $stg_username,
    m_password     => $stg_password,
    m_emailAddress => \@stg_email_addresses,
};

print_record($ellb_rec);